diff --git a/Android/AndroidPlatform.cs b/Android/AndroidPlatform.cs
index 6ec3779..0feca84 100644
--- a/Android/AndroidPlatform.cs
+++ b/Android/AndroidPlatform.cs
@@ -111,13 +111,16 @@ namespace Android {
             this.activity.StartActivity(new Intent(Intent.ActionView, Uri.Parse("https://play.google.com/store/apps/details?id=de.ellpeck.touchytickets")));
         }
 
-        public override void GainAchievement(Achievement achievement) {
-            if (this.GoogleApi != null)
+        public override bool GainAchievement(Achievement achievement) {
+            if (this.GoogleApi != null && this.GoogleApi.IsConnected) {
                 GamesClass.Achievements.Unlock(this.GoogleApi, AchievementIds[achievement.Name]);
+                return true;
+            }
+            return false;
         }
 
         public override void ShowAchievements() {
-            if (this.GoogleApi == null)
+            if (this.GoogleApi == null || !this.GoogleApi.IsConnected)
                 return;
             var intent = GamesClass.Achievements.GetAchievementsIntent(this.GoogleApi);
             this.activity.StartActivityForResult(intent, ShowAchievementsRequest);
diff --git a/TouchyTickets/Achievement.cs b/TouchyTickets/Achievement.cs
index e49d116..24f3795 100644
--- a/TouchyTickets/Achievement.cs
+++ b/TouchyTickets/Achievement.cs
@@ -48,8 +48,8 @@ namespace TouchyTickets {
                 return;
             if (!this.condition.Invoke(GameImpl.Instance))
                 return;
-            GameImpl.Instance.Platform.GainAchievement(this);
-            this.unlocked = true;
+            if (GameImpl.Instance.Platform.GainAchievement(this))
+                this.unlocked = true;
         }
 
         public static void Register(Achievement achievement) {
diff --git a/TouchyTickets/Platform.cs b/TouchyTickets/Platform.cs
index 9abe5bc..5501323 100644
--- a/TouchyTickets/Platform.cs
+++ b/TouchyTickets/Platform.cs
@@ -11,7 +11,7 @@ namespace TouchyTickets {
 
         public abstract void OpenRateLink();
 
-        public abstract void GainAchievement(Achievement achievement);
+        public abstract bool GainAchievement(Achievement achievement);
 
         public abstract void ShowAchievements();
 
diff --git a/iOS/IosPlatform.cs b/iOS/IosPlatform.cs
index b3b4374..828cb16 100644
--- a/iOS/IosPlatform.cs
+++ b/iOS/IosPlatform.cs
@@ -20,7 +20,7 @@ namespace iOS {
             throw new System.NotImplementedException();
         }
 
-        public override void GainAchievement(Achievement achievement) {
+        public override bool GainAchievement(Achievement achievement) {
             throw new System.NotImplementedException();
         }